BOSTON – State public health officials on Saturday announced the first human case of Eastern equine encephalitis in Massachusetts in six years and raised the risk level for the virus to critical in nine communities in Bristol and Plymouth counties.

Laboratory testing confirmed the EEE infection in a person the Department of Public Health described as a man over 60 from southern Plymouth County. EEE has been found in 227 mosquito samples this year, the department said. Public Health Commissioner Dr. Monica Bharel said news of a human case "is evidence of the significant risk from EEE and we are asking residents to take this risk very seriously."

The nine municipalities at "critical risk" for EEE are Carver, Lakeville, Marion, Middleborough, Rochester, Wareham, Acushnet, Freetown and New Bedford. Fifteen other communities in southeastern Massachusetts are at high risk for EEE, and 18 at moderate risk.

The DPH and the Massachusetts Department of Agricultural Resources announced last week they would be conducting and monitoring aerial spraying in parts of Bristol and Plymouth counties, and residents are also advised to use mosquito repellent and consider staying indoors at dawn and dusk.